Heterointerface-Engineered SiC@SiO₂@C Nanofibers for Simultaneous Microwave Absorption and Corrosion Resistance

To meet the demands of maritime defense and transportation, next-generation microwave absorption (MA) materials must combine efficient attenuation and corrosion resistance (CR). SiC nanofibers, with their moderate dielectric constant and chemical inertness, are ideal multifunctional coating fillers. However, their single-component nature limits microwave attenuation, resulting in low efficiency and narrow bandwidth. Incorporating corrosion-resistant components and employing heterointerface engineering offers a promising strategy to enhance polarization loss and synergistically improve CR. In this study, SiC nanofibers synthesized via chemical vapor deposition are used as precursors; SiO₂ interlayers and nitrogen-doped carbon shells are sequentially introduced to form multilayered core-shell nanofibers. Abundant heterointerfaces and defects effectively regulate impedance matching and introduce multiple loss mechanisms, including conduction, interfacial, and defect-induced dipole polarization. The prepared SiC@SiO₂@C (SSC) nanofibers achieve a minimum reflection loss of -52.40 dB, a maximum effective absorption bandwidth of 7.68 GHz, and a maximum radar cross-section reduction of 38.42 dB m², demonstrating excellent MA properties. Moreover, SSC/polyvinylidene fluoride (PVDF) composite coatings exhibit superior CR performance, with significantly enhanced corrosion potential and reduced current density compared to pure metal and PVDF coatings. This study underscores the synergistic effect of heterointerface engineering in enhancing both MA and CR for harsh environments.